Numerical Heat Transfer Model Of Ground Heat Exchanger And Ground Thermal Conductivity Measurement

This thesis has established a two-dimensional numerical transient heat transfer model of the ground temperature field around a buried U-tube Ground Heat Exchanger (GHE)..Combined with the parameters estimation methods, ground thermal conductivity was obtained by comparing the calculated U-tube fluid mean temperatures by the heat transfer model and the test values in situe.Delaunay triangulation method was used in the computational domain around geothermal heat exchanger, and the soil around the buried area was divided into a number of triangular elements. And then, the vertical unsteady temperature distribution around the buried pipe was solved. The triangular cell shape and density can be changed:Triangular elements were divided smaller in the region near pipe where the temperature changed relatively sharp;At the same time, elements were relatively large in the region far away from the pipe,Bye this way, without increasing the elements number, the solving region achieved good approximation, and has great flexibility and adaptability, and then the calculation accuracy was improved and computation cost reduced also.This thesis has also developed an analysis software with friendly human-machine interface which can rapidly analyse the data got from In-situ measuring. Two parts are mainly included:computation program and human-machine interface. The main program included a on the numerical ground heat transfer module and a parameters estimation method. It can be easily used by the users,such as geological prospecting engineers.By the developed calculating and analysis software,ground thermal conductivity of an actual project site has been determined by analyzing the measured water temperature variation with time. Analysis showed that the measured thermal conductivity can be used for in engineering design.